GSO filters are made of high quality, solid plane parallel glass with excellent homogeneity. They are anti-reflection coated to prevent glaring and ghosting. All eyepiece filters are threaded to fit GSO and most other manufacturers 1.25" eyepieces and offer a full 26mm clear aperture.

#80A Blue - 30% VLT

A Blue filter provides detail in atmospheric clouds on Mars, increases contrast on the moon, brings out detail in belts and polar features on Saturn, enhances contrast on Jupiter's bright areas and cloud boundaries. A blue filter is also useful in helping to split the binary star Antares when at maximum separation.